The proposed project is an anatomical investigation of the interconnections of the lateral posterior-pulvinar complex with the visual areas of the cortex in the cat. The aim of this investigation is to identify the specific populations of thalamic neurons which are involved in interconnecting the visual areas of the lateral suprasylvian cortex, and to systematically describe their connectional patterns. The investigation will employ electrophysiological mapping in combination with anterograde and retrograde axon tracing techniques at both the light microscopic and electron microscopic level to systematically explore interconnections between visual areas of the cortex and thalamus. It is expected that the anatomical observations of this project will provide a basis for future experimentation into the neural mechanisms for perceptual and visuomotor integration in the cat. Lessons learned in the cat have considerable application toward understanding visual processes in other mammals including man. Advances made in understanding the fundamental organization of the visual system may suggest new clinical approaches to treatment of visual dysfunctions which accompany central nervous system damage in man.